The use of soft contact lenses for reasons of cosmetics and for the correction of visual acuity is well known. Typically, these lenses are manufactured by casting. The mold halves used in the casting of the lenses are produced by first machining metallic inserts and then using the inserts to produce the mold halves. The process of machining the inserts may cause periodic defects, or periodic structures, that may be transferred to the mold halves. The molding surfaces of the mold halves are adequate to produce optical quality lenses for conventional hydrogel lenses cast in the mold halves.
However, in the cast molding of silicone hydrogel lenses, the silicone hydrogel materials precisely replicate the mold surface. Thus, periodic structures on the mold surface are transposed onto the lens' surface. If the lens is coated with a swellable, or hydrophilic coating, the swelling of the coating magnifies these surface defects. These magnified defects may compromise the lens wearer's vision by generating coherent scattering (prismatic effect) or tool marks visible to the eye care practitioner. Thus, the molds may produce coated silicone hydrogel lenses with surfaces of less than optical quality. Therefore, a need exists for a method and materials to overcome this problem.